During the initial stage of this research, properties (x-ray, chemical analysis, swelling test, cation exchange capacity, and amount of clay) of bentonite samples were determined. The concentration effect on the rheological properties of bentonite suspension was determined at six different concentrations (20, 22.5, 24, 26, 28, and 30 gr/350 ml). Fann viscometer dial readings were measured at ten varying rates of shear600, 300, 200, 100, 60, 30, 20, 10, 6, and 3 rpm. A three-parameter Robertson-Stiff model, describing the flow of non-Newtonian fluid by mathematical equations in terms of shear rate and shear stress, were studied; parametric analysis was also performed.